After four days with a sore throat and three days of having blackened urine, a 12-year-old Canadian boy arrived at the Hospital for Sick Children in Toronto. Interestingly, in addition to the previous symptoms, the boy also had a yellow tongue and a pale appearance on his skin. After a series of tests, therefore, doctors identified the condition, a rather rare autoimmune disorder.

It turns out that the boy developed a form of jaundice. This condition causes a yellowish appearance of the skin and eyes, mainly due to the death of red blood cells, as we will see later. However, this boy's jaundice was different. The condition happened, thus, because of the Epstein-Barr virus, from the herpes family.

Like other herpesviruses, the Epstein-Barr virus is quite common in humans, and is transmitted mainly by saliva. In the case of this Canadian boy, however, the infection of this herpes triggered an autoimmune response that ended up destroying many red blood cells. When the destruction of these cells occurs, bilirubin accumulates in the blood and, in this case, the body is unable to remove thisThis, therefore, causes the yellowish appearance of the skin and the yellow tongue.

It is because of bilirubin, by the way, that the urine is yellow. This is because old or destroyed RBCs end up in the liver and kidneys, mainly, so that their remains are excreted in the urine. Being a byproduct of RBC destruction, therefore, this compound is excreted as well. Hence the reason for the Canadian boy's too dark urine.

Autoimmune response and yellow tongue

Image: Narupon Promvichai / Pixabay

There are hundreds of autoimmune diseases and conditions. As the name implies, an autoimmune condition occurs when an individual's immune system fails to recognize some structure in the body. In this boy's case, the Epstein-Barr virus caused a temporary impairment of the immune response.

In other words, the cells responsible for protecting the body ended up recognizing the RBCs as foreign bodies. Thus, the boy's red blood cell count ended up lower than the reference value. Thus, the child needed a RBC transfusion as well as immunosuppressive treatment to prevent the immune system from continuing to attack his own cells.

After 2 days of hospitalization and 7 weeks of treatment with immunosuppressive steroids, the boy recovered from the symptoms, the viral infection and the yellow tongue, as it is possible to check in the medical report of the case.

Report available on The New England Journal of Medicine website.